• Alexey Kuznetsov's avatar
    [TCP]: Don't over-clamp window in tcp_clamp_window() · 09e9ec87
    Alexey Kuznetsov authored
    From: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
    Handle better the case where the sender sends full sized
    frames initially, then moves to a mode where it trickles
    out small amounts of data at a time.
    This known problem is even mentioned in the comments
    above tcp_grow_window() in tcp_input.c, specifically:
     * The scheme does not work when sender sends good segments opening
     * window and then starts to feed us spagetti. But it should work
     * in common situations. Otherwise, we have to rely on queue collapsing.
    When the sender gives full sized frames, the "struct sk_buff" overhead
    from each packet is small.  So we'll advertize a larger window.
    If the sender moves to a mode where small segments are sent, this
    ratio becomes tilted to the other extreme and we start overrunning
    the socket buffer space.
    tcp_clamp_window() tries to address this, but it's clamping of
    tp->window_clamp is a wee bit too aggressive for this particular case.
    Fix confirmed by Ion Badulescu.
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
tcp_input.c 124 KB